System of motor control.



H. D. JAMES.

SYSTEM OF MOTOR CONTROL. APPLICATION FILED AUG. 2. 1913.

1,175,359. Patented Mar. 14, 1916.

ATTORNEY UNITED STATES PATENT onrion.

HENRY ID. JAMES, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOB T WESTINGHOUSEELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF MOTOR CONTROL.

To all whom it may concern:

Be it known that I, HENRY D. JAMES, a citizen of the United States, anda resident of Edgewood, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Systems ofMotor Contrdl, of which specification.

My invention relates to systems of motor control, and it has particularreference-to I such systems as are employed in the operation of printingpresses and machines of a similar character.

My invention has for its object to provide a simple and effective meanswhereby various kinds of machinery operated by electric power may bedriven slowly at a uniform speed.

Inthe operation of a printing press, it is necessary to start itgradually and without shock to avoid tearing the paper in the rolls anddisturbing'the adjustment ofthe various parts. It is desirable to drivethe press at a low speed during the preliminary work of making up orpreparing for the regular operation and it is also desirable that thedrive be at a uniform speed during this period.

According to my present invention, I provide a main motor for drivingthe machinery during normal operation and an auxiliary motor forcontrolling the speed of the main motor while the press is being startedor driven slowly. The auxiliary motor may be of small capacity and beconnected to the machinery through gear mechanism having a large speedreduction. The small motor is so connected as to operate as a motor whenthe speed of the main motor decreases and to act as a generator when themain motor speeds up.

The details of my invention will be described in connection with theaccompanying drawings, in which'- Figure 1 is a diagrammatic view ofcircuits and apparatus embodying my invention. Fig. 2 is a diagrammaticview of a schematic arrangement of the motor circuits.

Referring particularly to Fig. 1, a main motor 1 and an auxiliary motor2 are'provided with a suitable controller 3. The controller 3 comprisesa movable arm 4:, the position of which is controlled by a pilot motor 5through a worm and gear mecha the following is a Specification ofLetters Patent. Patented Man 14 1916. Application filed August 2, 1913.Serial No. 782,562.

nism indicated at 6. The controller also comprises sectional resistors 7and 8 for controlling the armature and the field circuits, respectively,of the auxiliary motor 2, and resistors 9 and 10 for controlling thecorresponding respective circuits of the main motor 1. v

The motors are supplied with current from line conductors 11 and 12through line switches 13 and let, which are provided with actuatingcoils 15 and 16 and through an overload relay coil 17 A switch 18, thatis provided with a coil 19, controls the dynamic braking circuit of themain'motor 1.

The operation of the pilot motor 5 is controlled by switches 20, 21 and22 having corresponding actuating coils 23, 24 and 25.

The switches 20, 21 and 22, which are mechanically and electricallyinterlocked, control the connections of resistors-26, 27 and 28 to thecircuits of the pilot motor 5. The switches 20, 21 and 22 are controlledby duplicate sets of push buttons 29, 30, 31, 32, 33 and 34 which may belocated at convenient points upon the printing press or other. machine(not shown) to be operated. The actuation of the several push buttonscause the pilot motor to shift the arm 4' to produce the followingefi'ects upon the operation of the main motor and the auxiliary motor,

\ when the latter is connected in circuit: 29, 'start or fast; 30, slow;31, slow down; 32,-

stop; 33, run; and 3 1, safe. 7

As illustrated in Fig. 2, the shafts of the motors 1 and 2 are soarranged as to be mechanically connected by a reduction gear mechanism34 and' a friction clutch 35. The clutch is controlled by a lever 36that is actuated by a magnet core 37 against the force of a spring 38.The magnet core 3'? is surrounded by a coil 39 that is in series withthe armature of the motor 2-=and operates to maintain the clutchconnection while. the circuit of the motor 2 is closed and toautomatically release the clutch when the auxiliary motor circuit isbroken.

It may be assumed that the respective motors are stationary and that thearm 4 is in a position corresponding to that shown in Fig. 2. One of thepush buttons 29 is closed to complete a circuit which extends from theline conductor 11 through conductor 40, limit switch 80,.which is in itslower position, conductors 73 and 55, switch 54, coils 15 and 16 inparallel, switch member 51, conductor 46, switch member 47, conductor48, switch 29, switches 33, conductor 50, switches 32 and conductor toline conductor 12. The coils l'5 and 16 are thus energized to close theline switches 13 and 14. The closing of switch 13 operates to connectthe line conductor 11 directly to conductor 55 and thuseliminates aportion of the circuit above traced. The closing of switch 14 causes theswitch member 51 to be shifted upwardly and the circuit above tracedextends from the switch member 51 through conductor 50, switches 32 and.conductor 85 to line conductor 12. The closing of switch 14 alsocompletes a circuit ,which extends from the conductor 11 through theconductor 40, limit switch 41, conductor 42, switch 43, coil 24,conductor 44, switch 45, conductor 46, swich 47, conductor 48, switch29, conductor 49, switches 33, conductor 50, switches 32 and conductor85 to line conductor 12. The coil 24 is thus energized to draw theswitch 21 upwardly to complete the circuits of the pilot motor 5. Thearmature circuit extends from the conductor 11 through conductors 40,60, switch 21, resistors 26 and 27, conductor 61, pilot motor armature,conductors 62, 63, switch 64, conductors 6 5, 66, 67 to conductor 12.The field circuit extends from conductor 11 through conductor 40, fieldwinding 68, conductors 69 and 67 to conductor 12. The pilot motor nowactuates the arm 4 to complete the circuits of the motors 1 and 2. Thearm 4 first engages contact segments 70, 71 and contact pieces 72. Themotors 1 and 2 are connected in parallel, having circuits in commen fromthe conductor 11 through conductor 40, line switch 13, conductors 73, 74to arm 4. The arm 4 is connected through contact segment 71, resistor 9,contact segment 75, armature of motor 1, field windings 76, 77,conductor 78, coil '17, line switch 14 and line conductor 67 toconductor 12. The arm 4 is also connected through contact pieces 72,resistor 7, contact segment 79, magnet coil 39, armature of motor 2 toconductor 78,

and thence to the conductor12, as above traced. The coil 39 istherebyenergized to draw the core 37 inwardly to connect the members ofthe clutch 35. The arm 4 is so adjusted that the proper speed isobtained during the preliminary operations.

The main motor 1 will rotate very slowly because of the high resistanceof its armature circuit and'will consequently operate at an unstablepoint in its characteristic curve. The auxiliary motor 2 will run atapproximately its normal speed and will, therefore, tend to maintain auniform speed. T

Since the motors are connected in paral lel, the motor 2 will actasa'motor or as a generator according as the motor 1 decreases orincreases the speed of the system. The

speed of the system is thus maintained subincense stanti-ally uniformduring the preliminary operation of making up when the main drivingmotor is running slowly with a light load and is, therefore, subject tofluctuations in speed.

When the press is ready for normal operation, the pilot motor 5 isoperated to actuate the arm 4 to take the running position. The arm 4operates in succession to gracl'ually cut out the resistor 7 and toinsert the resistor 8 in the field circuit of the motor 2. When the arm4 leaves the contact segment 79, the circuit of the motor 2 is brokenand the coil 39 is thereby denergiaed to permitthe spring 38 todisengage the members of the clutch 35. The arm 4 then gradually cutsout the resister 9 and, at the end of this operation, inserts sectionsof the resistor 10 in the shunt field circuit of themotor to weaken thefield and thereby increase the speed of the motor. The motor 1 then runsat its normal speed to actuate the press during the regular operation.Further movement of the arm 4 to the left is limited by a limit switch41 while a limit switch 80 performs the same otlice at the other end ofthe range of movement of the arm. It will be understood that theposition of the arm 4 and the rate at which it changes or modifies therespective circuits are controlled by the several push buttons throughthe pilotmotor 5, the efiect of the actuation of the various buttonsbeing as above noted. a

While T-have described the details of my invention, it is understoodthat such changes may be made therein as fall within the limits of theappended claims.

I claim as my invention:

1. The combination with a plurality of motors, of means for operativelyconnecting the same, means for substantially simultaneously completingthe circuits of said motors, and means controlled by the circuitconditions of one of said motors for automatically disconnecting saidmotors.

2. The combination with a plurality of motors, and means for operativelyconnecting the same, means for operating one of said motors as agenerator when the speed of another motor exceeds a predetermined rate,and means for controlling said connecting means. I v

3. The combination with a plurality of motors,- and automaticallycontrolled means for mechanically connecting the same, of means foroperating one of said motors as a generator when the speed increases andas a motor when the speed decreases." J

4. The combination with a main motor and an auxiliary motor, of meanscomprising said auxiliary motor for controlling the speed of said mainmotor when the same is operated at a low rate of speed.

5. The combination with a main motor,

of means for controlling the speed of said main motor when operating ata low rate of speed, said means comprising an auxiliary motormechanically connected to said main motor, and means for disconnectingsaid motors when the main motor operates at a high rate of speed.

6. The combination with a plurality of motors, and means for operativelyconnecting them, of means for operating one of said motors as agenerator when their speeds exceed predetermined normal rates and as amotor when their speeds fall below said rates.

7. In a control system, the combination with a plurality of electricdriving motors, and means for operatively connecting said motors, of amaster switch for controlling the circuits of said motors and forcontrolling said connecting means, said switch 0pcrating tosimultaneously complete the circuits of said motors and to effect theiroperative connection.

8. In a control system, the combination with a plurality of electricdriving motors,

means for operatively connecting said motors, and electro-responsivemeans in circuit with one of said motors for controlling said connectingmeans, of a master switch for simultaneously closing the circuits ofsaid m0- tors and for opening the circuit of said motor that is incircuit with said electro-responsive means.

9. In a control system, the combination with a plurality of electricdriving motors, and means for operatively connecting said motors, of amaster switch which operates successively to simultaneously complete thecircuits of said motors and to effect their operative connection, breakthe circuit of one motor and disconnect said motors and accelerate asecond motor.

In testimony whereof, I have hereunto subscribed my name this 28th dayof July 1913.

HENRY Di JAMES.

IVitnesses 2 REED S. HAWK, B. B. HINES.

